Apparatus for the continuous coating of individual supporting elements

ABSTRACT

This invention relates to an apparatus for the continuous coating with a liquid material of a plurality of individual supports which comprises means for passing the supports past a coating die, means for forming a small accumulation of liquid material on the die orifice prior to the arrival at the orifice of a support to be coated, and means for feeding a constant quantity of the liquid material through the orifice onto the support as the latter passes the orifice.

United States Patent 1 1 Stroszynski 1 Apr. 29, 1975 1 1 APPARATUS FOR THE CONTINUOUS COATING OF INDIVIDUAL SUPPORTING ELEMENTS [75] Inventor: Joachim Stroszynski. Naurod,

Germany [73] Assignee: Hoechst Aktiengesellschaft,

Wiesbaden-Bicbrich, Germany [22] Filed: Jan. 28. 1971 [21] Appl. No.: 110,720

Related U.S. Application Data [62] Division of Scr. No 743.459. July 9. 1968.

abandoned.

[52] U.S.Cl 118/410; 117/119.8

[51] Int. Cl ..B44d1/08;B05c 11/12;B65h 3/10 [58] Field of Search 117/119.8, 120; 118/407, 1 18/410 [56] References Cited UNlTED STATES PATENTS 1,594,583 8/1926 Wood 118/411) 3.088334 5/1963 Spraguc 1 18/410 3.227.136 1/1966 Bartlett ct a1 118/410 3.431.139

3/1969 Stroszynski 117/1198 Primary Eranziner-Henry S. Jaudon Attorney, Agenl, or Firm-James E. Bryan [57] ABSTRACT This invention relates to an apparatus for the continuous coating with a liquid material of a plurality of individual supports which comprises means for passing the supports past a coating die, means for forming a small accumulation of liquid material on the die orifice prior to the arrival at the orifice of a support to be coated. and means for feeding a constant quantity of the liquid material through the orifice onto the support as the latter passes the orifice.

3 Claims, 8 Drawing Figures -ggpngmiazs m5 SHEET 1 EF 2 ATTORNEY P 755m 2 9 ms SHEET 2 OF 2 INVENTOR ATTORNEY APPARATUS FOR THE CONTINUOUS COATING OF INDIVIDUAL SUPPORTING ELEMENTS This application is a division of copending application Scr. No. 743.459. filed July 9. 1968 now abandoned.

It is known to perform the continuous coating of endless supports by spraying. whirl-coating or coating by means of dies but these processes can not be employed for coating individual supporting elements. particularly when a high uniformity of the layer thickness also in the end portions of the support is necessary and the coating material must not contact the base on which the support lies during coating. A satisfactory process for the continuous coating of individual supporting elements has not been known hitherto.

The present invention provides a process for the continuous coating of a plurality of individual supports with a liquid material. in which the supports successively pass a slot die covering them with a coating of the liquid material. The material is fed to the die via'a proportioning system consisting of two pumps with slides working without fluid displacement and is periodically controlled in a manner such that a constant quantity is fed by means of one pump over the total area of the support and the other pump. at the proper moment before a support arriving at the die contacts the material. additionally forms a small accumulation of material on the orifice of the die.

The apparatus for the performance of the process of the invention comprises a proportioning system regulating the feed of material. which consists of two infinitely. and independently. regulatable pumps with adjacent slides working without tluid displacement which. in addition to an opened stage. also have a by-pass stage the position of which can be periodically regulated at the proper intervals.

By means of this apparatus. a small defined accumulation of liquid is formed on the lips of the coating die. which accumulation contacts an individual supporting element passing it without wetting the base. on which the element is mounted. in advance of the element. No interruption of the liquid film results and, upon contact. the individual sheet or support is uniformly coated. At the end of the support. the feed of material is interrrupted for a brief interval by means of suitable indexing elements.

The invention is further illustrated by the accompanying drawings. in which:

FIGS. 1 and 2 show a support passing a die.

FIG. 3 shows the proportioning system of the invention.

FIGS. 4 to 6 are diagrams of the chronological sequence of the coating operation. and

FIGS. 7 and 8 show an advantageous embodiment of the slide employed.

FIG. I shows an individual support 2 mounted on a curved suction base I and immediately before contact with a liquid accumulation 3 on the lips ofa coating die 4. The support also may be mounted on the base in another manner, e.g.. magnetically. as long as an absolutely plane position is guaranteed.

FIG. 2 shows the coating operation after the support has contacted the liquid accumulation.

FIG. 3 shows a rotating drum 5 on which an individual support 6 is mounted and which passes a coating die 7 illustrated in section. The coating die is fed by means of a proportioning system consisting of the two pumps 8, 9 and the associated slides 10. 11. The slide 10 is open as is further illustrated in FIG. 8 and the slide II is in the by-pass position as is shown in FIG. 7. The pumps withdraw the coating liquid from the supply container I2.

The method of operation of the proportioning system can be seen in the diagrams of FIGS. 4 to 6 which show the chronological sequence. In order to form the accumulation of liquid on the die. which is necessary for a satisfactory contact. the feed of material has to begin a short time A t before the support arrives at the die (FIG. 6). the two pumps independently supplying the quantities G, and G; into the coating die. One of the two pumps supplies the quantity G necessary for uniform coating and the other supplies the quantity G additionally necessary for the sudden formation of the accumulation of liquid. The two pumps thus may operate without difficulty and independently of each other at the required rate of revolution. Since the speed may be infinitely varied. the quantities G and G can be adapted to the requirements resulting from different widths of the supports. During operation. the two pumps normally run at a once adjusted rate of revolution. As can be seen from FIG. 5. the feed of material must be interrupted for a brief interval A tbefore the time at which the support has passed the die so that the coating material cannot flow onto the base.

Since it is necessary that. during opening and closing of the supply conduits. no displacement of fluid occurs. sliders are employed which guarantee this. FIGS. 7 and 8 show proportioning pumps with such sliding elements. FIG. 7 illustrating the by-pass position and FIG. 8 illustrating the through or open position. Between an upper cover plate 13 having an inlet opening 15 and a lower cover plate 14 having the passages 16 and 17, there are two proportioning meshing gear wheels I8 and 19. one mounted behind the other as viewed in FIGS. 7 and 8 and one being driven by means of the shaft 20. Numeral 21 indicates the slide tongue with lateral slots 22, which tongue. in the case of FIG. 7. provides for a connection between the two passages 16 and 17 by means of the channel 23 and. in the case of FIG. 8. opens the outlet 24. The slots 22 permit the flow of fluid from one end of the slide to the other upon opening or closing thereof. As required. the slides are rapidly actuated to the open or to the by-pass position. e.g.. pneumatically or e'lectromagnetically. The impulses for opening and closing the slider elements are generated mechanically. optically, pneumatically or electrically. Mechanical indexing elements may be mounted on a rotating drum. for example. which close and open the slides at the proper intervals or cause them to do so by means of a pneumatic system. for example. It is advantageous to employ photoelectric cells which scan the support arriving on the base and which control the operation of the slides at appropriate time intervals. The time intervals should be such that an accumulation of fluid is formed before the leading edge of an individual support passes by the coating die. Furthermore. after the support has contacted the liquid. care should be taken to obtain the required coating thickness without adverse influences. Apart from very short initial and end zones. the coating thickness remains constant from one end of the support to the other. The base is not wetted.

The problem to uniformly coat individual supports on one side over their entire area is thus easily and satisfactorily solved by the process of the present invention.

It will be obvious to those skilled in the art that many modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.

What is claimed is:

1. An apparatus for the continuous coating with a liquid material of a plurality of individual supports which comprises means for passing the supports past a coating die, means for forming a small accumulation of liquid material on the die orifice prior to the arrival at the orifice of a support to be coated, and means for feeding a constant quantity of the liquid material through the orifice onto the support as the latter passes the orifice. said means for forming the small accumulation of liquid in the die orifice and said means for feeding a constant quantity of the liquid material through the orifice including a pair of infinitely and independently regulat- Lil able pump means.

2. An apparatus according to claim 1 in which the pump means include slide means which operate without displacement of fluid to the orifice.

3. An apparatus for the continuous coating with a liquid material of a plurality of individual supports which comprises a coating die. means for passing individual supports past the coating die. a first pump for forming a small accumulation of liquid material of the die orifice prior to the arrival at the orifice of a support to be coated. and a second pump for feeding a constant quantity of the liquid material through the orifice onto the support as the latter passes the orifice. each of said first and second pumps having a by-pass and a slide operating without displacement offluid, said first and second pumps being infinitely and independently regulatable, and each of the slides having one position to produce by-pass flow and another position to produce feed UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3 3 880 117 DATED April 29, 1975 |NVENTOR(S) Ioaohim Stroszynski It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Item has been omitted and should read Foreign Application Priority Data Iuly 12, 1967 Germany 1652348 Signed and Scaled this fourth Day Of November 1975 sen] Attes t: 

1. An apparatus for the continuous coating with a liquid material of a plurality of individual supports which comprises means for passing the supports past a coating die, means for forming a small accumulation of liquid material on the die orifice prior to the arrival at the orifice of a support to be coated, and means for feeding a constant quantity of the liquid material through the orifice onto the support as the latter passes the orifice, said means for forming the small accumulation of liquid in the die orifice and said means for feeding a constant quantity of the liquid material through the orifice including a pair of infinitely and independently regulatable pump means.
 2. An apparatus according to claim 1 in which the pump means include slide means which operate without displacement of fluid to the orifice.
 3. An apparatus for the continuous coating with a liquid material of a plurality of individual supports which comprises a coating die, means for passing individual supports past the coating die, a first pump for forming a small accumulation of liquid material of the die orifice prior to the arrival at the orifice of a support to be coated, and a second pump for feeding a constant quantity of the liquid material through the orifice onto the support as the latter passes the orifice, each of said first and second pumps having a by-pass and a slide operating without displacement of fluid, said first and second pumps being infinitely and independently regulatable, and each of the slides having one position to produce by-pass flow and another position to produce feed flow. 